HYDEOID ZOOPHYTES. 41 



tacula ; one row surrounds the middle of the heads^ and 

 the other is placed round the mouth. Bulbules clustered, 

 shortly pedicled, placed within and at the base of the lower 

 tentacula ; embryo not always the same, being sometimes in 

 the form of a Beroe, sometimes of a hydra/' 



This Tuhular'ia indivisa is the largest of its tribe in 

 Great Britain. The tubes, on which the hydra-heads are 

 placed, grow some five or six inches long on shells and 

 stones in deep water. They look like scarlet flowers on the 

 ends of long twisting worms. They congregate in clusters 

 of thirty or forty specimens, and make a splendid nosegay 

 of living and moving flowers. The tubes are horny and 

 transparent, showing the reddish liquor through them, and 

 the polypes at the end have two rows of tentacles." 



We must again hear the eloquence of Sir J. Dalyell : — 

 "The yellow, fistulous stem, full of mucilaginous pith, 

 is rooted on a solid substance below, and crowned by 

 a living head, resembling a fine scarlet blossom, with a 

 double row of tentacula, and often with pendent clusters 

 of grapes, embellished by various hues, wherein red and 

 yellow predominate. Fifty, or even a hundred and fifty, 

 are at times crowded together; their heads, of diverse 

 figures, shades, and dimensions, constitute a brilliant, ani- 



